Tool steel

ABSTRACT

The invention provides a novel metallic composition and method of using the same. More particularly, the invention affords a tool steel and a method of heat treating the tool steel. In one of the preferred embodiments the tool steel includes about 0.50 to about 0.65 percent by weight carbon, about 0.095 to about 1.70 percent by weight manganese, up to about 0.030 percent by weight phosphorus, about 0.095 to about 0.200 percent by weight sulfur, about 1.10 to about 1.90 percent by weight chromium, about 0.10 to about 0.50 percent by weight nickel and about 0.20 to about 0.60 percent by weight copper. The tool steel of the present invention is preferably heat treated utilizing a heat treatment schedule that includes the steps of a preheat, austenization and a double temper.

This is a divisional of application Ser. No. 08/264,135 filed on Jun.22, 1994, now U.S. Pat. No. 5,505,798.

FIELD OF INVENTION

The present invention concerns a metallic composition and a method ofusing the same. More particularly, the invention concerns a tool steeland a method of using the tool steel produce tools, dies or similaritems.

BACKGROUND

The prior art provides various tool steels for use in producing itemssuch as tools and dies. Such tool steels are generally classified as:(i) relatively low-alloy tool steels having higher hardenability thanplain carbon steels; (ii) intermediate alloy steels which usuallycontain elements such as tungsten, molybdenum or vanadium, which formhard, wear resisting carbides; and (iii) high-speed tool steelscontaining large amounts of carbide forming elements which serve notonly to furnish wear resisting carbides but also to promote secondaryhardening and thereby increase resistance to softening at elevatedtemperatures.

The relatively low-alloy and intermediate tool steels are commonlyemployed to produce dies which are utilized to shape, form, bend, draw,cut or otherwise process low carbon steels, stainless steels andaluminum. Such materials prior to processing may assume any one of avariety of configurations such as, for example, bars, rods, strips orsheets. The automotive industry, which does a considerable amount ofmetal processing, utilizes various low-alloy and intermediate alloy toolsteels to produce dies. Such dies are commonly employed in presses andare used to produce items such as, for example, hoods, fenders, roofdecks and trunk lids. The automotive industry places some fairlycritical demands upon the tool steels from which their dies areproduced. More particularly, many automotive dies undergo a considerableamount of machining and grinding in order to allow the die to produceitems of intricate shape and exacting size tolerances. Also, automotivedies are many times used to process a tremendous number of items and arethus subject to very long runs. Additionally, some automotive dies arevery large in size and require a considerable amount of tool steel intheir production. Thus, preferably the tool steel does not include majoramounts of expensive alloying elements because the cost of the toolsteel itself can be a significant factor in the construction of thedies.

An example of one tool steel utilized by the automotive industry toproduce dies is a tool steel sold by the Uddeholm Corporation ofSterling Heights, Mich. under the trademark FERMO. Generally, FERMO toolsteel would be classified as a relatively low-alloy tool steel havingabout 0.45 to 0.52 percent by weight carbon, 0.75 to 1.05 percent byweight manganese, 0.40 to 0.80 percent by weight silicon and 1.30 to1.70 percent by weight chromium. FERMO tool steel is preferred by someautomotive personnel because it tends not to distort during flamehardening. Also, FERMO tool steel may be welded cold therebyfacilitating repair of the die while it is mounted in the press orsimilar machine. Thus, such dies do not have to be removed from thepress thereby helping to minimize costly downtime. Unfortunately, FERMOtool steels generally display a maximum Rockwell (R) hardness on theC-scale (Rc) of about 54 to 58. Thus, FERMO tool steel is generally notsuited for long runs where a die is scheduled to be utilized to producea great number of items or pieces.

An example of another tool steel utilized by the automotive industryincludes about 0.85 to 1.0 percent by weight carbon, 0.20 to 0.30percent manganese, 0.20 to 0.30 percent by weight silicon and 0.15 to0.25 percent by weight vanadium. This tool steel is preferred by someautomotive personnel because it can be repair welded in the press.However, flame hardening of this tool steel is conducted at atemperature of about 1600° F. to 1650° F. followed by a water quench.Unfortunately, distortion has been found many times to develop duringthis hardening treatment.

An example of another tool steel utilized by the automotive industryincludes about 0.85 to 1.10 percent by weight carbon, 0.50 to 0.70percent by weight manganese, 0.25 to 0.40 percent by weight silicon,4.75 to 5.25 percent by weight chromium, 0.20 to 0.40 percent by weightvanadium and 0.95 to 1.20 percent by weight molybdenum. This tool steelis commonly flame hardened at a temperature of about 1800° F. or higherand generally displays a Rockwell hardness on the C-scale of around 60.This tool steel usually cannot be repair welded while the die is in thepress. Generally, the damaged die, or sections thereof, must be removedfrom the press and preheated prior to repair welding. This can be atime-consuming process leading to costly downtime.

Another tool steel utilized in the automotive industry includes about0.45 to 0.55 percent by weight carbon, 1.0 to 1.20 percent by weightmanganese, 0.30 to 0.50 percent by weight silicon, 1.00 to 1.25 percentby weight chromium and 0.35 to 0.45 percent by weight molybdenum. Thisalloy is generally supplied in an annealed condition having a Brinellhardness number (BHN) of about 180 to 220. Flame hardening of this toolsteel is generally conducted at a temperature of about 1780° F. followedby a water quench to produce a Rockwell hardness on the C-scale of about58 to 60. Problems experienced by some automotive personnel with thistool steel include distortion during flame hardening and a relativelylow wear resistance.

Generally, the aforementioned steels are formed into dies while the toolsteel is in an annealed and/or normalized condition. In order to attainthis condition, such tool steels are generally annealed and/or subjectedto a normalization treatment until the desired hardness is attained.

Relatively low alloy tool steels are also used in some applications toproduce tools such as chisels. An example of a tool steel that was atone time utilized to produce chisels contained about 0.35 percent byweight carbon, 0.70 percent by weight manganese, 0.45 percent by weightsilicon, 0.80 percent by weight chromium, 0.30 percent by weightmolybdenum and 0.30 percent by weight copper. This tool steel waspreferred for such applications as chisels because of its tendency notto become brittle and break during use. This tool steel generally wouldnot be used to produce dies because of its inability to consistentlyproduce Rockwell hardnesses on the C-scale in excess of about 54.

A recently developed flame hardenable tool steel and methods of heattreating such steel are disclosed in U.S. Pat. Nos. 5,182,079 and5,055,253. These patents disclose a tool steel comprising by weight0.50-0.65 percent carbon, 0.090-1.45 percent manganese, up to about0.030 percent phosphorus, 0.035-0.070 percent sulfur, 1.10-1.90 percentchromium, 0.15-0.40 percent nickel and 0.20-0.40 percent copper. The'079 patent discloses two different heat treat schedules. One scheduleconcerns castings over 120 pounds and the other schedule concernscastings below 120 pounds. Generally, for castings below 120 pounds thetool steel is preheated, austenitized and double tempered. For castingsabove 120 pounds the tool steel is normalized followed by air-cooling.

SUMMARY OF INVENTION

The present invention provides a new and improved metallic composition.More particularly, the present invention provides a novel relativelylow-alloy tool steel for use in producing tools, dies and other similaritems. The tool steel is particularly well suited for use in producingdies for the automotive industry.

The tool steel affords various distinct advantages over many prior arttool steels. Specifically, the tool steel of the present invention maybe flame hardened by a user with virtually no distortion. This allows anend user to finish machine and grind the die in a soft (i.e.,pre-hardened) condition and flame harden the die while it is mounted inthe press just prior to final die try out or just prior to production.Similarly, the tool steel allows the die to be repair welded while thedie is mounted in the press or machine. Also, the tool steel allows thedie to be finished while the tool steel is in a pre-hardened fullymachinable condition having a Rockwell hardness on the C-scale of about30 to about 38. The tool steel also provides case hardening depths ofabout three-sixteenths of an inch to about three-eighths of an inchduring flame hardening thereby helping to ensure long runs for diesproduced utilizing the tool steel. Furthermore, since the tool steeldoes not contain major amounts of expensive alloying elements, it is arelatively inexpensive material for use in the production of dies andsimilar items. Finally, the tool steel of the present invention affordssignificantly improved machinability over the tool steels disclosed inU.S. Pat. Nos. 5,182,079 and 5,055,253.

The tool steel includes up to about 0.85 percent by weight carbon, about0.95 to about 1.70 percent by weight manganese, about 0.095 to about0.200 percent by weight sulfur, about 1.0 to about 2.0 percent by weightchromium and about 0.10 to about 0.50 percent by weight nickel.Preferably, the tool steel also includes at least about 0.20 percent byweight copper.

Prior to converting the tool steel into a die, and subsequent to castingthe tool steel, it is preferably subjected to a heat treatment schedule.During the heat treatment schedule the tool steel is initiallypreheated, then austenitized and finally double tempered. During thepreheat, preferably the tool steel is heated to an equalizationtemperature of about 1000°-1200° F. and soaked for about one to threehours for every inch of cross section based upon the heaviest section ofthe tool steel. While the tool steel is in the furnace at temperaturethe austenization cycle is initiated. During austenization the toolsteel is preferably heated to an equalization temperature of about1625°-1675° F. for about one to three hours for each inch of crosssection based upon the heaviest section of the tool steel and then takendown to an equalization temperature of about 1475°-1525° F. and held atthis temperature for about thirty to about ninety minutes for each inchof cross section based upon the heaviest section of the tool steel. Thetool steel is then cooled to a temperature of from about 200° F. toabout 500° F. During the first temper the tool steel is preferablycharged into a furnace having a temperature of about 1100° F. to about1300° F. and held at temperature for about two to about four hours foreach inch of cross section based upon the heaviest section of the toolsteel followed by air-cooling to room temperature. During the secondtemper the tool steel is preferably heated to an equalizationtemperature of about 1100° F. to about 1300° F. and held at temperatureabout four to six hours per inch of cross section based upon theheaviest section of the tool steel.

The above heat treatment schedule produces a Rockwell hardness on theC-scale of about 30 to about 38. In this condition, the tool steel maybe easily machined or otherwise worked into a tool, die or other item.Subsequent to working, the tool steel may then be flame hardened at atemperature of about 1560° F. to produce a Rockwell hardness on theC-scale of between about 60 and 62 and a case depth of aboutthree-sixteenths of an inch to about threeeighths of an inch.

The foregoing and other features of the invention are hereinafter morefully described and particularly pointed out in the claims, thefollowing detailed description and the annexed drawings setting forth indetail certain illustrative embodiments of the invention, these beingindicative, however, of but a few of the various ways in which theprinciples of the present invention may be employed.

BRIEF DESCRIPTION OF DRAWINGS

In the annexed drawings:

FIG. 1 is a perspective view of a die made in accordance with theprinciples of the present invention; and

FIG. 2 is a schematic partial cross section of the die of FIG. 1 mountedin a press.

DETAILED DESCRIPTION

The present invention provides a relatively low-alloy tool steelsuitable for use in producing any one of a variety of items such as, forexample, tools, dies, knives, punches and molds. However, the tool steelis particularly well suited for use in producing dies. The tool steel isparticularly well suited to dies subject to demanding applications suchas the dies employed by the automotive industry.

Shown in FIG. 1 is a die 10 produced utilizing applicant's tool steel.For the purposes of this specification, and the claims below, a die isdefined as a tool that imparts shape to solid, molten or powdered metalbecause of the shape of the tool itself. Such dies are used in variouspress operations including blanking, drawing, forming, in die castingand in forming green powder and metallurgy compacts. Die 10 ispreferably machined or ground to its final shape while the die 10 is ina pre-hardened or soft condition. Once the die 10 has been worked to itsfinal configuration, the working surface 12 of the die 10 is then flamehardened. Illustrated in FIG. 2 is a press 15 in which die 10 ismounted. As a result of the application of pressure imparted by thepress 15 upon the die 10 and the punch 20, a workpiece 22 is formed intoa finished or semifinished part.

As is well-known in the art, tool steels are metallic compositions thatpredominately contain iron and are alloyed with various other elementssuch as, for example, carbon, manganese, chromium, nickel andmolybdenum. Tool steels are generally characterized by high hardness andresistance to abrasion.

The tool steel of the present invention is produced utilizingconventional melting practices to provide a tool steel having up toabout 0.85 percent by weight carbon, about 0.095 to about 1.70 percentby weight manganese, about 1.0 to about 2.0 percent by weight chromiumand about 0.10 to about 0.50 percent by weight nickel. In order toenhance machinability, the tool steel includes a very high level ofsulfur, from about 0.095 to about 0.200 percent by weight sulfur. Quiteunexpectedly, applicant has found that this high level of sulfur can beused to significantly improve machinability without the development ofundesirable properties such as poor surface quality, poor weldability,brittleness, cracking, poor strength, etc.

Preferably, the tool steel includes copper and is killed or deoxidizedutilizing primarily, but not exclusively, silicon. Also, preferably theamount of phosphorus contained in the tool steel is limited. In anotherpreferred embodiment the tool steel includes about 0.4 to about 0.8percent by weight carbon, about 0.105 to about 1.65 percent by weightmanganese, up to about 0.050 percent by weight phosphorus, about 0.105to about 0.190 percent by weight sulfur, from about 0.30 to about 0.90percent by weight silicon, about 1.10 to about 1.90 percent by weightchromium, about 0.15 to about 0.40 percent by weight nickel and fromabout 0.20 to about 0.60 percent by weight copper. More preferably, thetool steel comprises about 0.50 to about 0.65 percent by weight carbon,about 1.15 to about 1.60 percent by weight manganese, up to about 0.050percent by weight phosphorus, about 0.110 to about 0.175 percent byweight sulfur, about 0.40 to about 0.85 percent by weight silicon, about1.15 to about 1.85 percent by weight chromium, about 0.15 to about 0.40percent by weight nickel, and from about 0.20 to about 0.55 percent byweight copper.

In a further preferred embodiment of the invention the tool steelcomprises about 0.52 to about 0.68 percent by weight carbon, about 1.25to about 1.55 percent by weight manganese, up to about 0.030 percent byweight phosphorus, about 0.110 to about 0.165 percent by weight sulfur,about 0.50 to about 0.80 percent by weight silicon, about 1.20 to about1.75 percent by weight chromium, about 0.15 to about 0.35 percent byweight nickel, and from about 0.25 to about 0.50 percent by weightcopper.

Preferably, like phosphorus, other residual elements contained in thetool steel are controlled such that iron accounts for at east about 90.0percent by weight of the tool steel. More preferably, iron accounts forat least about 92.0 percent by weight of the tool steel. Moreparticularly, preferably, the amount of residual molybdenum contained inthe steel is limited to about 0.30 percent by weight, and morepreferably it is limited to about 0.20 percent by weight of the toolsteel. Likewise, preferably the vanadium contained in the tool steel islimited to about 0.020 percent by weight, and more preferably, it islimited to about 0.010 percent by weight of the tool steel.Additionally, preferably the cobalt (Co) contained in the tool steel islimited to about 0.05 percent by weight of the tool steel. Additionally,preferably the tungsten (W) contained in the tool steel is limited toabout 0.03 percent by weight of the tool steel. Also, preferably thetitanium (Ti) contained in the tool steel is limited to about 0.001percent by weight of the tool steel. Additionally, preferably thenitrogen (N) contained in the tool steel is limited to about 0.01percent by weight of the tool steel. The presence of excess amounts oftitanium, vanadium, nitrogen, molybdenum, tungsten, cobalt and otherhardening agents may cause excessive undesirable hardeningcharacteristics in the tool steel.

The tool steel preferably includes aluminum (A1). Preferably, the toolsteel comprises from about 0.03 percent to about 0.30 percent by weightaluminum. More preferably, the tool steel comprises from about 0.05percent to about 0.25 percent by weight aluminum.

The tool steel is preferably cast at a temperature of between about2825° F. and about 2860° F. Preferably, the molds in which the toolsteel is cast are stripped at about 600° F. and the tool steel is thenallowed to air-cool to room temperature. Any one of a variety of steelmelting techniques and/or processes may be utilized to produce the toolsteel. For example, an electric furnace, basic oxygen furnace or aninduction furnace may be utilized to produce the molten tool steel.Likewise, any one of a variety of casting techniques may be employedsuch as top pour molds, bottom pour molds, sand molds, metal molds or acontinuous caster may even be employed. Further, the tool steel may becast into any one of a variety of shapes such as, for example, blooms,billets, ingots, bars or into the pattern of a die. Preferably, the toolsteel is cast to its near final desired shape. However, if necessary,subsequent to stripping the tool steel may be heated to a suitabletemperature and hot-worked into alternative shapes.

Subsequent to stripping and cooling, the tool steel is then preferablysubjected to a heat treatment schedule. The heat treatment schedulesoftens the tool steel thereby facilitating the cutting, machining, orother operations that may be utilized to convert the as cast tool steelinto a die or similar item. More particularly, the heat treatmentschedule refines the grain structure of the as cast tool steel placingit in a pre-hardened condition suitable for machining, grinding andflame hardening with substantially no distortion.

The heat treatment schedule includes preheating, austenization and adouble temper. Preheating is performed by heating the tool steel to anequalization temperature of about 1000° F. to about 1200° F., andpreferably about 1100° F. where it is held at temperature for about oneto about three hours for every inch of cross section based upon thethickest or heaviest section of the tool steel, and preferably about twohours per inch of such cross section. As used herein this specificationand the claims below, the term "equalization" refers to a substantiallyequal, homogeneous or uniform temperature throughout the piece orsection of tool steel.

Immediately after the preheat, while still in the furnace, austenizationis performed. Austenization is initially performed at an equalizationtemperature of about 1625° F. to about 1675° F., and preferably about1650° F. The tool steel is held at this equalization temperature forabout one to about three hours per inch of cross section based upon thethickest section of the tool steel, and preferably two hours for eachinch of such cross section. The tool steel is then taken down to anequalization temperature of about 1475° F. to about 1525° F., andpreferably about 1500° F. and held at this equalization temperature forabout thirty to ninety minutes per inch of cross section based upon thethickest section of the tool steel. The tool steel is then air-cooled toan equalization temperature of from about 200° F. to about 500° F., andpreferably from about 250° F. to about 450° F. Depending on the type offurnace utilized, a nitrogen purge or circulation fans may be utilizedto promote cooling.

The first of the tempers is performed at an equalization temperature ofabout 1100° F. to about 1300° F., and preferably about 1200° F. for aperiod of between about two and about four hours per inch of crosssection based upon the thickest section of the tool steel, andpreferably about three hours per inch of such cross section. The toolsteel is then air-cooled to ambient or room temperature. The secondtemper is performed at an equalization temperature of about 1100° F. toabout 1300° F., and preferably about 1200° F. for a period of betweenabout four and six hours per inch of cross section and preferably aboutfive hours per inch of such cross section. Preferably, during each ofthe tempers the tool steel is charged into a furnace or oven which hasbeen preheated to temperature.

Subsequent to heat treatment, the tool steel is in a prehardenedcondition and it generally displays a Rockwell hardness of about 30 toabout 38 on the C-scale. Preferably, the tool steel does not display aRockwell hardness in excess of 39 on the C-scale. In this pre-hardenedcondition, the tool steel is relatively easy to machine, grind orotherwise process into a die such as die 10 shown in FIG. 1. Since thetool steel is relatively soft, it is unlikely to chip or break duringsuch processing. As used herein this specification, and the claimsbelow, "Rockwell" on the "C-scale" refers to hardness values obtainedusing a standard sphero-conical diamond penetrator.

Once the tool steel has been fully processed and finished into a die 10,the die 10 may then be post-hardened in a furnace, oven or similarheating device. Preferably, the die 10 is flame hardened and air-cooledalong the working surface 12 in order to produce a Rockwell hardness onthe C-scale of about 60 to about 62, with virtually no distortion.During flame hardening, case depths of between about three-sixteenths ofan inch to about three-eighths of an inch may be attained on the workingsurface 12. Preferably, flame hardening is accomplished by heating thesurface of the tool steel to a temperature of between about 1530° F. toabout 1600° F., and preferably about 1560° F., followed by air-cooling.This flame hardening step may be carried out while the die 10 is mountedin the press 15. Similarly, the die 10 may be repair welded in the press15 without any preheating. Applicant has found that when repairingcracks in castings such as dies made from the tool steel of the presentinvention, subsequent to welding and filling the crack, the repairedweld area should be lightly peened prior to flame hardening.

In order to further illustrate the invention, the following example isprovided below.

EXAMPLE I

In an induction furnace a tool steel melt is formed having a compositioncomprising 0.60 percent by weight carbon, 0.65 percent by weightsilicon, 1.4 percent by weight manganese, 0.01 percent by weightphosphorus, 0.120 percent by weight sulfur, 1.50 percent by weightchromium, 0.25 percent by weight nickel, 0.40 percent by weight copper,0.09 percent by weight aluminum and residual amounts of nitrogen,titanium, cobalt, tungsten, vanadium and molybdenum. The tool steel meltis cast at about 2845° F. and poured into molds which form 20 poundcastings having a thickest or heaviest cross section of about one inch.The molds are stripped at a temperature of about 600° F. and then thecastings are air-cooled to room temperature. Preheating is performed byheating the castings to an equalization temperature of about 1100° F.where they are held at temperature for about two hours. Immediatelyafter preheating, while the castings are still in the furnace, theaustenization cycle is initiated. Austenization is initially performedat an equalization temperature of about 1650° F. The castings are thenheld at this equalization temperature for about two hours. The castingsare then taken down to an equalization temperature of about 1500° F. andheld at this equalization temperature for about one hour. The castingsare then air-cooled and quenched in a nitrogen purge. The first of thetempers is performed at an equalization temperature of about 1200° F.for a period of about two hours and then the castings are air-cooled toroom temperature. The second temper is performed at an equalizationtemperature of about 1200° F. for a period of about five hours. Thecasting are then air-cooled to room temperature. Subsequent to heattreatment the castings display a Rockwell hardness of about 33 on theC-scale. The castings are then machined into dies and flame hardened.During flame hardening the work surface of the castings are heated to atemperature of about 1560° F. followed by air cooling. Subsequent toflame hardening the dies display a Rockwell hardness of about 62 on theC-scale.

It will be appreciated that although the above description has beenprimarily focused upon dies, the tool steel of the present invention isalso well suited for use in producing various other items such aspunches, knives, blades and any other variety of items where theproperties of a tool steel are desired.

Although the invention has been shown and described with respect topreferred embodiments, it is obvious that equivalent alterations andmodifications will occur to others skilled in the art upon reading andunderstanding the specification. The present invention includes all suchequivalent alterations and modifications, and is limited only by thescope of the following claims.

What is claimed:
 1. A metallic composition comprising iron (Fe), fromabout 0.40 to about 0.80 percent by weight carbon (C), from about 0.095to about 1.70 percent by weight manganese (Mn), up to about 0.030percent by weight phosphorus (P), from about 0.095 to about 0.200percent by weight sulfur (S), from about 1.00 to about 2.00 percent byweight chromium (Cr), from about 0.30 to about 0.90 percent by weightsilicon (Si), from about 0.10 to about 0.50 percent by weight nickel(Ni), up to about 0.010 percent by weight vanadium (V), up to about 0.20percent by weight molybdenum (Mo), less than about 0.05 percent byweight cobalt (Co), less than about 0.03 percent by weight tungsten (W),less than about 0.001 percent by weight titanium (Ti) and from about0.03 to about 0.30 percent by weight aluminum (Al), said compositionhaving been subjected to a heat treating process which includes anaustenization step and a tempering step.
 2. A composition as set forthin claim 1 including the step of tempering such composition for a secondtime.
 3. A composition as set forth in claim 1 wherein prior to saidaustenization step such composition is preheated.
 4. A composition asset forth in claim 1 wherein during said austenization step suchcomposition is initially heated to an equalization temperature of fromabout 1625° F. to about 1675° F. for a period of from about one to aboutthree hours for about every inch of cross section measured at thethickest portion of such composition, then such composition is heated toa temperature of from about 1475° F. to about 1525° F. for from aboutthirty to about ninety minutes for about every inch of cross sectionmeasured at the thickest portion of such composition.
 5. A compositionas set forth in claim 1 wherein during said austenization step. suchcomposition is heated to an equalization temperature of about 1650° F.for a period of about one hour for about each inch of cross section atthe thickest portion of such composition and then such composition isheated to an equalization temperature of about 1500° F. for about onehour for each inch of cross section measured at the thickest portion ofsuch composition.
 6. A composition as set forth in claim 1 whereinsubsequent to said austenization step and prior to said tempering stepsuch composition is cooled to an equalization temperature of from about200° F. to about 500° F.
 7. A composition as set forth in claim 1wherein such composition is cooled to an equalization temperature offrom about 250° F. to about 400° F. subsequent to said austenizationstep and prior to said tempering step.
 8. A composition as set forth inclaim 1 wherein during said tempering step such composition is heated toan equalization temperature of from about 1100° F. to about 1300° F. forabout from two to about four hours for about each inch of cross sectionmeasured at the thickest portion of such composition.
 9. A compositionas set forth in claim 1 wherein during said tempering step suchcomposition is heated to an equalization temperature of about 1200° F.for about three hours for about every inch of cross section measured atthe heaviest portion of such composition and subsequent to saidtempering step such composition is air-cooled to room temperature.
 10. Acomposition as set forth in claim 2 wherein during said second temperingstep such composition is heated to an equalization temperature of fromabout 1100° F. to about 1300° F. for a period of about four to six hoursfor about each inch of cross section measured at the thickest portion ofsuch composition.
 11. A composition as set forth in claim 3 whereinduring said step of preheating such composition is heated to anequalization temperature of from about 1000° F. to about 1200° F. forfrom about one to about three hours for about every inch of crosssection measured at the heaviest portion of such composition.
 12. Acomposition as set forth in claim 3 wherein during said step ofpreheating such composition is heated to an equalization temperature ofabout 1100° F. for about two hours for about every inch of cross sectionmeasured at the heaviest portion of such composition.
 13. A compositionas set forth in claim 1 including the steps of machining suchcomposition so as to structurally form a die or tool; and flamehardening such composition.
 14. A composition as set forth in claim 1wherein such composition comprises a tool or a die.
 15. A metalliccomposition as set forth in claim 1 wherein said composition includesfrom about 0.20 to about 0.60 percent by weight copper (Cu).